Turbo Boost problem with RHEL 6 - HP DL580 G7 w/ four x7550 Processors

[Paul Rubin_1]

We've been struggling with the RedHat folks for over a month now to get Turbo Boost to operate correctly on a HP DL580 G7 w/ four x7550 Processors. No matter what we try, under load or no load, turbostat always reports all cores at TSC 2.00 and GHz at 2.13. The cores should be capable of scaling up to 2.4 GHz.

The data in the RHEL sosreport indicates that Linux is aware that these processors are turbo-boost capable, and Linux can see the ida processor flag.

Among the things we've tried are:

OS Control Mode BIOS setting vs Performance BIOS setting.

scaling_governor at userspace vs performance

add processor.nocst to etc/grub.conf

Does anyone have any ideas about how to get TurboBoost to work properly?

[Naresh_Kumar]

Hyperboost depends on the following factors:

*             Number of active cores

*             Estimated current consumption

*             Estimated power consumption

*             Processor temperature

Test with following setups:

1. Go to BIOS/RBSU enable only one core per processor.
2. Reboot login to OS and install turbostat.
3. Test using command . /turbostat issued from where the application is installed.

Image attached

Note: Turbo boost frequency achieved depends primarily on number of cores active at the same time. As the number of active cores increases the max achievable turbo boost frequency decreases. This means with only one core enabled per processor the highest turbo boost frequency can be achieved.

For example when one core was enabled per processor I was able to see the processor clocking 2.26 GHZ which is the max documented achievable turbo boost frequency. When six cores per processor enabled we could only reach 2.13 GHz.

The setup I used consist of a DL580G7 with 2x E7540 processors with 2.0 GHZ base frequency (which can be achievable 2.26 GHz with Turbo boost option enabled) Refer http://ark.intel.com/products/46492/Intel-Xeon-Processor-E7540-%2818M-Cache-2_00-GHz-6_40-GTs-Intel-QPI%29

Please find the wiki link useful in calculating frequency with regards to cores enabled on processors under example section.

http://en.wikipedia.org/wiki/Intel_Turbo_Boost